You get files for three variations of a printable N scale (1:160) wood trestle bridge: two single track versions and one double track. The files can be rescaled such as for HO (1:87) scale. Also included is a Sketchup file. The Sketchup file is water tight, print ready, and can be edited and rescaled. Note that the scaling in the Sketchup file is ten times larger than the scale size due to Sketchup performing poorly at tiny scales. Most of the N scale pieces should fit most dlp printers.